This invention relates to a storage or cargo caddy system designed to fit into or supplant an air fairing of a ground traveling vehicle. Specifically, it is intended to be compatible with air fairings commonly used on trucks and semi-tractors, which function to present aerodynamic transition between the lesser height of the vehicle cab and the greater height of the cargo body or semi-trailer. The storage or cargo caddy system is modular in design, and is made to be easily inserted into and removed from the space defined by the air fairing.